Vought F4U Corsair

Vought F4U Corsair was one of the most successful and renowned fighter aircraft of World War II. Developed since 1938, it didn’t make it to serial production until mid-1942. Initially disqualified by the US Navy for carrier service, it was handed over to land-based US Marine Corps fighter units, where it soon proved its worth in combat.

It was fast, robust and heavily armed, which also made it an excellent weapon against ground targets. When it was finally qualified for carrier operations, before long it became (along with F6F Hellcat) the primary aircraft of US Navy fighter and fighter-bomber squadrons.

The Concept

In early 1935 BuAer (Bureau of Aeronautics) of the US Navy issued a request for proposals for a new carrier-based fighter aircraft, a future successor of biplane fighters Boeing F4B and Grumman FF, operated by the Navy at that time, as well as Grumman F2F and F3F, which were shortly to enter service. The Navy accepted XF2A-1, the project submitted by Brewster company. The prototype, powered by Wright R-1820 Cyclone engine, was first flown in December 1937. BuAer also ordered – as an alternative, in case Brewster’s project failed to meet expectations – Grumman’s new fighter powered by Pratt & Whitney R-1830 Twin Wasp engine, which soon evolved from biplane XF4F-1 to monoplane XF4F-2. The prototype XF4F-2 was first flown in September 1937, even earlier than its competitor, but problems with its powerplant slowed down its development. Hence, F2A-1 Buffalo entered service as the first US monoplane carrier-based fighter. Eventually however, it was the Grumman fighter, the improved F4F-3 model later known as Wildcat, which proved a much more capable aircraft and in early forties became the standard US Navy carrier fighter.
Meanwhile, on 1st February 1938, a few months after first flights of XF4F-2 and XF2A-1, BuAer offered a tender for yet another carrier fighter. The new aircraft was expected to reach at least 350 mph (563 kph) maximum speed at 20,000 feet (6096 meters), have stall speed no higher than 70 mph (113 kph) and range of 1000 miles (1609 km). It was to be armed with four machine guns. As was the case three years earlier, BuAer didn’t insist on any particular powerplant or design concept, besides the obvious requirement that the aircraft was capable of operating from carrier decks. In fact, for the Navy the priority was the aircraft’s high performance, especially maximum speed. BuAer was so focused on this factor that it became a standing joke among Vought designers, who claimed that the Navy gave them only three requirements: firstly – speed, secondly – speed, thirdly – more speed.

corsair 1

In response to this latest tender, in April 1938 Chance Vought Aircraft Division of United Aircraft Corporation, based at East Hartford, Connecticut, submitted two projects of a classic, single-engined, single-seat fighter: V-166A (known to BuAer as Vought A), powered by a proven R-1830 Twin Wasp engine, and V-166B (Vought B) powered by a new XR-2800 Double Wasp engine constructed by Pratt & Whitney, still under development at that time. The latter powerplant was a huge, two-row, 18-cylinder radial engine with a displacement of 2800 cubic inches (45.9 l). The prototype XR-2800-2 (B-series) was equipped with two-stage, two-speed supercharger with intercooler. Its maximum rated power on takeoff was 1,850 hp at 2,600 rpm, and it could develop 1,500 hp of continuous power at 2,400 rpm (at 17,500 ft). In comparison, the XR-1830-76 engine powering XF4F-3 prototype produced only 1,200 hp on takeoff and 1,000 hp at 19,000 ft.
The designers from Pratt & Whitney expected soon to increase the takeoff power to 2000 hp. The R-2800 was the first American 18-cylinder engine and the first producing such enormous power for its time. The decision to mount it in a new aircraft design was a risky one, for it was a completely new and unproven powerplant; on the other hand, there was a good chance that the Navy would get its desired high-performance fighter.1
BuAer, having analyzed all submitted proposals, selected the one referred to as the Model V-166B and powered by XR-2800-2 engine. On 11th (or 30th, according to other sources) June 1938 Vought was awarded a contract No. 61544 authorizing the company to build a prototype of the new fighter, which was given military designation XF4U-1 and serial number (BuAer Number, BuNo) 1443. The same month BuAer signed a similar contract with Grumman for building a prototype of XF5F-1, a twin-engined fighter, and in November also with Bell for building XFL-1 prototype powered by Allison V-1710 inline engine. Of these three very novel fighter aircraft designs, only Vought XF4U-1 made it to serial production.

The Design

The team of designers working on technical details of XF4U-1 included Frank C. Albright (as project engineer, replaced in January 1941 by John Russell “Russ” Clark); Paul S. Baker and William C. Schoolfield (as aerodynamics engineers); James Shoemaker and Donald J. Jordan (propulsion engineers). The overall supervision of the project was given to Rex Buran Beisel, the company’s chief engineer. Beisel also had a decisive voice in choosing particular design solutions.